Portable cylinder grinder



March 24, 1931. M. N. PRANGE PORTABLE CYLINDER GRINDER Filed June 14, 1926 2 Sheets-Sheet 1 March 24, 1931. N, PRANGE PORTABLE CYLINDER GRINDER Filed June 14, 1926 2 Sheets-Sheet 2 snow H01 J9 Naor/ce NEW/7c Patented Mar. 24, 1931,

PATE T OFFICE,

' MAURICE 1v. .P RANGE, on 1331030152, MICHIGAN r PORTABLE QQYLINIDER GRINDER Applieation filed June 14,

This invention relates to a lapping tooland particularly to a portable device of this character employed for lapping or grinding en- 'gine cylinder'sfwithout removing the engine 7 v from .its bed.

An object of the invention is to produce a device of this character having a rigid construction which ensures an accurate grinding or lapping at all times.

Another QbjeCtOf the invention is toprovide a construction providing for anniversal mounting of the grinding stones, this mounting being capable of reversibly receiving the grinding stones,so that upon becomingworn they may be reversed.

- Another advantageous feature of this invention resides in the skeleton frame construction upon which the shoes carryingthe grinding stones are mounted, this arrangement facilitating .the assembling and repair- .ing of the device. v

Another advantageous structural feature consists inthe' form of the shoes upon which the stones are carried, whereby the axially traveling adjusting members for the several shoes may impart a greater range of adjustment, within a given distance, owing to the fact that the cam grooves'forrned in the shoes extend pastthe' both directions. a

' Various other objects of theinvention and additional features of construction, as well as the details'of construction and operation of the device, will be made more apparent as plane of the shoe cavities in this description proceeds, especially when considered in connection with the accompanying drawings, wherein:

Figure 1 is a side elevation of a lapping tool constructed in accordance with my invention. Figure 2 is a 1 vertical sectional View through'the tool. I

. FigureB is an enlarged horizontal section taken substantially on the plane indicated on the line 3 3 of Fig. 1.

Figure 4: is a perspective view of one of the stone-carrying shoes seen from the rear.

Figure 5 is a top plan view partly insection, certain of the parts being removed.

Figure 6 is a horizontal sectional view taken substantially in the plane indicated by 1926. Serial no. 116,004.

the line 6-6 of Fig. 1, looking in the direction of the arrows. t

Figure 7 is a perspective ton frameof the device; I

Figure 8 is a horizontal section showinga different-form of grinding stone; and

Figure 9 is an'inverted plan view of the plate of the universal connection.

Referring now particularly to the draw- ,ings, wherein like reference charactersindicate similar parts, it will be noted thatthe frame of the device consists of three members 10, having segmentaltop and bottom portions '11, which together form substantially the circular top and bottom plate members, these portions being connected by vertically-extending webportions 12. The segmental plate portions 11 of each ofthe members 10 are of such dimensions that,whenassembled, they provide three radiallyextending slots 13. The frame members 10 are united in their assembled relation, such as shown in Fig. 7 by means of cap plates 14. Each plate 14 is provided radially at points which align with the slots 13, withoutwardly bowed or dished 175 portions 15, whereupon radial channels are provided in which the heads of the stonecarrying shoes, yet to be described, are disposed in the assembled device. 7

In Figure 4 there is illustrated in perspective one of the stone-carrying shoes, as seen view of the skelefrom the rear. It will be noted that this shoe member 16 is provided with a pair of verticallyextending', spaced sockets 17 into which the grinding elements or stones are adapted to be clamped. The shoe is provided at both ends with a head 18 shouldered as at 19, thus producing reduced neck portions 20 which connect the heads 18 to the body of the shoe member. The shouldered portions 19 of. the

heads are" adapted to rest upon the upper and lower faces of the end plates of the skeleton frame'with the neck portions 20 riding in theslots 13. The arcuateportions' of the heads 18 fit in the-dished or bowed portions 15 of the cap or platemembers 14. Thu-s'the shoes 16, which are'here shown as three in number, are slidably supported in the skeleton frame and capable of radial displacementinwardly and outwardly with reference to the axis of the frame. The rear of each shoe member, as best shown in Fig. 4, is provided with a pair of cam grooves 21 which extend from points adjacent the heads 18 to within points adjacent the longitudinal center of the shoe. Here these cam slots terminate, the shoe being preferably cast with an enlargement thereon forming an abutment 22. The cam slots are also inclined with reference to the vertical plane of the shoe member, as more clearly shown in Fig.1 2,. these cam grooves starting at points adjacent the abutment 22 in a plane which is beyond the bot I adjustment is permitted within a given area than would otherwise be possible.

The stories, or grinding elements 23, are adapted to seat in the shoe cavities 17 in the 1113111161 clearly illustrated in Figure 3and are secured against accidental displacement by wedge members 24 secured to the plane face of each shoe member by means of bolts 25. It should be noted that the stones 23 are so mounted as to present only one vertical edge 26 in the grinding position. As will be apparent, the active edges of each pair of grinding stones are the adjacent edges, consequently when these edges have become worn the stones may be reversed, thus increasing the life of the stones. I

Extending vertically through the skeleton frame and constituting the centralvertica'l axis of the device-is an operating member in the form of'a doublescrew spindle 27 This member is journaled at its lower end on the lower cap plate 14 and is provided with a co1- lar 28 keyed thereto as at 29, which prevents axial displacement of the spindle 27. At its upper end the spindle passes freely through the upper cap plate 14 and is provided with a squared portion 30 which engages a squared aperture-31 in a clutch or ratchet plate 32. By this connection the plate 32 is adapted to be rotated with the spindle 27, for a purpose to be hereinafter more fully described. Moreover by reason of this connection a slight longitudinal movement of the spindle is permitted resulting in a lateral or rocking movement of the stones. This action is especially desirable in reconditioning cylinders which, 7

through wear develop slight variations in diameter. The extreme upper circular end 33 of the spindle 27 is journaled-in the circular aperture 34 of a head 35 which is of a spider construction in plan View, the spider arms 36 thereof being clamped against the surface of the cap plate 14 betwen the radially bowed portions 15 by means of bolts 37.

These bolts extend down through the cap plate 14 and into the circular head plate of the frame member. The head 35 is formed with one or more recesses in which are positioned spring pressed balls 38' which are adapted to engage the ratchet teeth 39 of the ratchet plate 32, to lock this plate and consequently the spindle 27 inits adjusted positions Portions of the circumference of the ratchet plate 32 are sufliciently exposed to permit this ratchet plate to be engaged bya screw-driver or other tool, whereupon it may be forcibly rotated during the operation of the grinding tool, to rotate the spindle 27 and consequently adjust the grinding stones in the mannerhereinafter more fully to be described.

Cooperating with the head 35 is a plate 40 suitably bolted thereto and partially defining a recess 41 formed in the head 35. The inner periphery of the plate 40 is provided with a plurality of cut-away portions 42 and a plurality ofperipheral abutment-s 43. A shank 44 suitably connected to a source of power I (not shown) is provided with a plurality of radially extending lugs 45 preferably equal in number to the cut-away portions 42, whereupon the shank may be inserted into the recess 41 of the head and rotated a quarter turn to bring the lug 45 into engagement with the shoulders or abutments 43 whereupon a nonrotative connection is established'between the shank and the head 35. Owing to the fact that the inner periphery of'the plate 40, ex-

cept at the cut-out portions 42, is undercut as shown-at 46, a semi-universal connection is established between the shank 44 and the machine. r

The'spindle 27 has a threaded engagement with a pair of cam members in the form of substantially triangular nuts 47. The arm portions 48 of the nuts 47 are adapted to slidably engage in the cam grooves 21 of the shoes 16, each cam member 47 engaging all three of the shoes 16, as clearly shown in Fig. 3. The threads on the spindle 27 extend in opposite directions from the center so that a rotation of the spindle will move the cam members 47 toward or away from one another axially of the device. As they move toward one another and inconsequenc e of the receding cam grooves the shoes are permitted to move radially inward to reduce-the grinding diameter of the device and as the cam members 47 move away from one another the shoes 16 are moved outwardly in a like manner.

Tensionmembers,.preferably in the form of coiled springs 49, are arranged around the ends of the three-shoes 16 to normally draw, these shoes radially inwardly, thereby holding the cam grooves 21 thereof in positive engagement with the arms 48 of the cam nuts 47.

In Fig. 8, the rectangular stones or grinding elements 23 are shown as replaced by circular stones which, it will be noted, may be properly seated in the shoe cavity 17 and have bearing engagement at points 51, 52, and 53. Thus'it will be seen that the shoe cavities 17 are universal in that the rectangularor round stones may both be properly seated.

In operation, the tool will be inserted into an engine cylinder and the shank, which is connected to a suitable source of power, is caused to engage in the head 35, there being, after the shank has been rotate-d a quarter turn, a non-rotative and semi-universal connection established therebetween. Power is then applied to rotatethe tool, whereupon the edge portions 26, if squarestones 23 are employed, engage the cylinder wall for grinding or lapping the same. As the grinding or lapping operation proceeds the circumference of the grinding tool may be increased by rotat ing the ratchet plate 32 by means of aitool or the like. This rotates the spindle 27 which causes cam nuts 47 to travel away from one another; engagementof these nuts with the camgrooves 21 of the shoes 16 moving the three shoes simultaneously outward a uniform distance. It should be noted that an outward pressure willbe exerted equally on andequally resisted by the tension members 49. vFurthermore, the arrangement of the parts is such that an absolutely rigid structure is presented, as there is an unyielding connection betweenthe cam nuts and the shoes and an unyielding connection between the shoes and the grinding stones.

Obviously, by means of the ratchet plate 32, the grinding stones may be adjusted while the tool is still within the, engine cylinder and the parts will be held in their adjusted position, first by reason of the threaded connection between the nuts 47 and the spindle 27 and secondly, by reason of the detent balls 38 which are spring pressed into engagement with the teeth 39 of the ratchet plate 32. As the active edges of the stones 23 become worn these stones may be reversed and as the active edges of the circular stones, commonly used, become worn, these stones may be rotated to likewise portion.

While but one embodiment of the invention has been here illustrated and described in detail, it will, be immediately apparent to those skilled in the art that various modifications may be resorted to without departing from the spirit and scope of this invention present a new unused and to this end reservation is made to make.

such changes as may come within the purview of the accompanying claims. j What I desire to claim as my invention is: 1'; In a lapping tool, a frame, stone holders mounted on said frame for radial adjustment, grinding elements rigidly supported by said holders, and means for positively adjusting said grinding elements to a predetermined diameter including a-pair ofcam members and cooperating cam surfaces formedlon said holders and inclining from points adjacent the-heads thereof. outwardly beyond the bottom walls of the stone holders to within points adjacent the longitudinal center of the holders.

2111 a lapping tool, a mounted on said frame for radial adjustment, each'of said stone holders formed with a pair of circumferentially spaced pockets, grinding elements positioned withinsaid pockets, positively actuated cammeans, and cam surfaces inclined outwardly from opposite ends of said holders and engageable: by said cam means for radially ad ustmg said stone holders. j g j 8. In a lapping tool, a frame, stone holders mounted on said frame for radial adj ustment,

each of said stone holders formed withv a pair of longitudinally extending pockets, grinding elements rigidly secured in said pockets,

positively actuated cam means and cam grooves arrangedupon said stone holders in termediate the pockets and engageable by said cam means for radially adjusting said stone holders.

4. In a lapping tool, a frame, stone holders mounted on said frame for radial adjustment, each of said stone holders formed with a pair of longitudinally extending spaced pockets, grinding elements'arranged within said pockets, cam members, and cooperating cam surfaces disposed between said pockets and inclining from points adjacent the inner surface of the heads of said stone holders outwardly to points substantially beyond the bottom of said pockets.

5. In a lapping tool, a frame comprising a plurality of members having segmental top and bottom portions, Vertically extending web portions connecting said top and bottom portions, cap plates for uniting said members in spaced relation to provide a plurality of radial slots, stone holders having a head portion and a reduced portion adjacent to said head portion slidably engaging said.

slots,said cap plates being formed with the embossed portions for receiving the heads of the stone'holders and cooperate therewith to prevent longitudinal displacement of said holders, and means for radially adjusting said stone holders.

6. In a lapping tool, a frame, stone shoes mounted for radial adjustment in said frame, said shoes bemg formed with stone cavlties frame, stone holders shaped to support both polygonal and annular shaped stones and means for rigidly con- 7 necting the stones to said shoes.

7. In a lapping tool, a frame, stone shoes mounted for radial adjustment in said frame, said shoes formed with stone cavities having irregular inner surfaces to adapt the shoes to accommodate stones of various configuration.

8. Ina lapping tool, a frame, a stone shoe carried by said frame and having a pocket therein for receiving a stone, said pocket having the interior surface shaped to support stones of various contours, and detachable means cooperating with the cavities for rigidly securing the stones to said shoes.

9 In a lapping tool, a frame, stone holders mounted on said frame for radial adjust-' ment, each of said stone holders formed with a a pair of pockets arranged circumferentially in juxtaposition to each other, grinding elements positioned within said pockets, positively actuated cam means and cooperating cam surfaces formed on said stone holders intermediate the pockets and adapted to be engaged by said cam means for radially. adjusting the stone holders.

In testimony Whereof'I affix my signature.

MAURICE N. PRANGE. 

